February 22, 2013, 12:00 pm - 1:00 pm

February 22, 12:00 pm - 1:00 pm

Effect of Interhemispherical Field-Aligned Currents on Disturbances in Polar Regions in Two Hemispheres

Inna (Sonya) Lyatskaya

In this presentation, the role of the Interhemispherical Field-Aligned Currents (IHCs) flowing between conjugate high-latitude ionospheres in two hemispheres is investigated. The IHCs, flowing between Northern and Southern high-latitude ionospheres, are generated because of difference in ionospheric conductivity in two polar regions, which is caused by seasonal and Universal Time variations of solar luminosity in two polar ionospheres, the asymmetry in positions of the geomagnetic poles, and other effects. The difference in ionospheric conductivity in two hemispheres and the magnitude of the IHCs are especially significant during summer / winter months, when these currents are comparable in magnitude with total Field-Aligned Currents (FACs). While crossing the equatorial plane, the IHCs do not change their direction. As a result, they increase the total FACs in one hemisphere, but decrease the total FACs in the opposite hemisphere, which leads to strong North-South asymmetry in total FACs as well as to specific geomagnetic and ionospheric disturbances in the polar regions. In this report, we present our recent research results on the role of IHCs in North-South asymmetry of geomagnetic and other disturbances in two hemispheres and propose a method that allows significant improving prediction reliability of these disturbances in two hemispheres. These results are important for better understanding of interaction between two hemispheres and many applied problems including the effect of the IHCs on the thermosphere and low-orbiting spacecraft.